Engineering of Mn3O4@Ag microspheres assembled from nanosheets for superior O3 decomposition

Manganese oxides have wide application in the ambient decomposition of ozone, although their activities are affected by many parameters. Morphology engineering and metal doping are, together, one of the most effective methods to enhance catalytic activity for O-3 decomposition. Herein, a topochemical transformation route to Mn3O4 nanospheres composed of 2D nanosheets is first provided by using layered beta-MnOOH as the precursor. Then, silver nanoparticles are deposited over the Mn3O4 nanosheets via a redox reaction without any extra reducing agents. In comparison with Mn3O4 with a conventional octahedral morphology, the prepared Mn3O4 nanosphere (Mn3O4-NF), and its Ag-doped composite, Mn3O4@Ag (Mn3O4@Ag-NF), both retain the morphology of beta-MnOOH, and display better reducibility and higher oxygen vacancies. The best catalytic performance for O-3 decomposition is found over Mn3O4@Ag-NF, which exhibits similar to 88.5% removal efficiency within 24 h at a space velocity of 600 L g(-1) h(-1) and a relative humidity of 50% at room temperature. This work emphasizes the advantages of nanosheet morphology and metal doping in optimizing the catalytic activity for O-3 elimination of manganese oxide.

Automated summary

The study utilized morphology engineering and metal doping to prepare Mn3O4 with excellent catalytic performance, with the Ag-doped Mn3O4@Ag composite showing the best catalytic activity for O-3 decomposition. The results demonstrate that the Ag-doped Mn3O4@Ag exhibits a removal efficiency of up to 88.5% for O-3 within 24 hours, highlighting promising applications in air purification.